mfd: lpc_ich: Avoton/Rangeley uses SPI_BYT method

Avoton/Rangeley are based on Silvermount micro-architecture, like
Bay Trail, and uses the INTEL_SPI_BYT method to drive SPI.

Cc: stable@vger.kernel.org
Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>